<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>

<form action="#">
  <input type="text" name="username" placeholder="用户名" value="admin"> <br>
  <input type="password" name="password" placeholder="用户密码" value="123"> <br>
  <input type="submit" value="登录">
</form>

</body>
</html>